How can I get rid of a scar that didn't heal properly after stitches? (Photo)

I have a raised scar on my upperarm that's two years old. After taking the stitches out, the wound opened up. It has a very negative connotation, being a self-harm scar. Now that I'm happy, I'd give anything to get rid of it. It upsets me everytime I look at it. I know there isn't a way to toy get rid of it, but I want to make it less noticable. I was considering getting a tattoo to cover it but wanted to know if there's anything that could make it skinnier. Thank you in advance!